Added the JNI interface to get and set RtpParameters and the maximum bitrate limits.

webrtc/api/java/jni/jni_helpers.h

Index: webrtc/api/java/jni/jni_helpers.h
diff --git a/webrtc/api/java/jni/jni_helpers.h b/webrtc/api/java/jni/jni_helpers.h
index 87c5ca48f22e1089bd8cf2ad39468cc17c82e8bb..ec5a45f8d2135ba293619135cfe548d2199cc3a2 100644
--- a/webrtc/api/java/jni/jni_helpers.h
+++ b/webrtc/api/java/jni/jni_helpers.h
@@ -17,6 +17,7 @@
 #include <jni.h>
 #include <string>
 
+#include "webrtc/base/constructormagic.h"
 #include "webrtc/base/checks.h"
 
 // Abort the process if |jni| has a Java exception pending.
@@ -122,6 +123,104 @@ class ScopedGlobalRef {
   T obj_;
 };
 
+// Provides a convenient way to iterate over a Java collection using the
+// C++ range-for loop.
+// E.g. for (jobject value : JavaCollection(jni, j_collection)) { ... }
+// Note: Since Java iterators cannot be duplicated, this class is not copyable
+// to prevent creating multiple C++ iterators that refer to the same Java
+// iterator.
+class JavaCollectionIterator {

[pthatcher1, 2016/03/21 21:57:00]

It would actually be JavaIterableIterator.

How about just webrtc_jni::Iterator?

[skvlad, 2016/03/21 22:27:39]

Done.

+ public:
+  // Creates an iterator representing the end of any collection.
+  JavaCollectionIterator() : iterator_(NULL) {}
+  // Creates an iterator pointing to the beginning of the specified collection.
+  JavaCollectionIterator(JNIEnv* jni, jobject collection) : jni_(jni) {
+    jclass j_class = GetObjectClass(jni, collection);
+    jmethodID iterator_id =
+        GetMethodID(jni, j_class, "iterator", "()Ljava/util/Iterator;");
+    iterator_ = jni->CallObjectMethod(collection, iterator_id);
+    CHECK_EXCEPTION(jni) << "error during CallObjectMethod";
+
+    if (iterator_ == NULL) {
+      // TODO(skvlad): Should this be an exception instead?
+      return;
+    }
+
+    jclass iterator_class = GetObjectClass(jni, iterator_);
+    has_next_id_ = GetMethodID(jni, iterator_class, "hasNext", "()Z");
+    next_id_ = GetMethodID(jni, iterator_class, "next", "()Ljava/lang/Object;");
+
+    // Start at the first element in the collection
+    ++(*this);
+  }
+
+  // Move constructor - necessary to be able to return iterator types from
+  // functions
+  JavaCollectionIterator(JavaCollectionIterator&& other)
+      : jni_(std::move(other.jni_)),
+        iterator_(std::move(other.iterator_)),
+        value_(std::move(other.value_)),
+        has_next_id_(std::move(other.has_next_id_)),
+        next_id_(std::move(other.next_id_)){};
+
+  // Move assignment should not be used.
+  JavaCollectionIterator& operator=(JavaCollectionIterator&&) = delete;
+
+  // Advances the iterator one step
+  JavaCollectionIterator& operator++() {
+    if (iterator_ == NULL) {
+      // Can't iterate past the end
+      return *this;
+    }
+    bool have_next = jni_->CallBooleanMethod(iterator_, has_next_id_);

[pthatcher1, 2016/03/21 21:57:00]

have_next => has_next

[skvlad, 2016/03/21 22:27:39]

Done.

+    CHECK_EXCEPTION(jni_) << "error during CallBooleanMethod";
+    if (!have_next) {
+      iterator_ = NULL;
+      return *this;
+    }
+
+    value_ = jni_->CallObjectMethod(iterator_, next_id_);
+    CHECK_EXCEPTION(jni_) << "error during CallObjectMethod";
+    return *this;
+  }
+
+  bool operator==(const JavaCollectionIterator& other) {
+    return (iterator_ == other.iterator_);
+  }
+
+  bool operator!=(const JavaCollectionIterator& other) {
+    return !(*this == other);
+  }
+
+  jobject operator*() { return value_; }
+
+ private:
+  JNIEnv* jni_ = NULL;
+  jobject iterator_ = NULL;
+  jobject value_ = NULL;
+  jmethodID has_next_id_ = NULL;
+  jmethodID next_id_ = NULL;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(JavaCollectionIterator);
+};
+
+class JavaCollection {

[pthatcher1, 2016/03/21 21:57:01]

webrtc_jni::Iterable?

[skvlad, 2016/03/21 22:27:39]

Done.

+ public:
+  using iterator = JavaCollectionIterator;
+  explicit JavaCollection(JNIEnv* jni, jobject collection)

[pthatcher1, 2016/03/21 21:57:01]

collection => iterable

[skvlad, 2016/03/21 22:27:39]

Done.

+      : jni_(jni), collection_(collection) {}
+
+  iterator begin() { return JavaCollectionIterator(jni_, collection_); }
+
+  iterator end() { return JavaCollectionIterator(); }
+
+ private:
+  JNIEnv* jni_;
+  jobject collection_;

[pthatcher1, 2016/03/21 21:57:00]

iterable_

[skvlad, 2016/03/21 22:27:39]

Done.

+
+  RTC_DISALLOW_COPY_AND_ASSIGN(JavaCollection);
+};
+
 }  // namespace webrtc_jni
 
 #endif  // WEBRTC_API_JAVA_JNI_JNI_HELPERS_H_